A number of devices for transmitting power and reducing motor output speed are currently known. Two such devices are the harmonic drive and the cycloidal drive.
The more well-known of these devices is the harmonic drive, having been introduced in the 1950's and currently being in wide-spread use. However, the harmonic drive requires the use of a flexspine, which is deliberately deformed repeatedly during operation of the harmonic drive. This deformation of the flexspine fatigues the material from which the flexspine is constructed, which fatigue limits the speed reduction and torque transfer that may be achieved with a harmonic drive.
Typical versions of the cycloidal drive are of relatively complex construction and operation. The cycloidal drive requires many moving parts, each of which may be a point of failure. In addition to being of complex design, cycloidal drives are typically not backdrivable. The eccentric rotation of the cycloidal disc also produces an undesirable vibration that may be transmitted through the input and output shafts if not compensated for. Finally, contact between the output rollers and the receiving holes in the cycloidal disc may also lead to the wear of both components.
What is needed is a power transmission/speed reduction device that does not suffer from the described drawbacks of known harmonic and cycloidal drives. Such a device may also offer a more simplistic construction, as well as a long life.